<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>过渡效果</title>
    <style>
        .box {
            height: 100px;
            width: 100px;
            background-color: thistle;
            /* background-image: url(images/png/aichong03.png); */
            /* 最后两个可以省略 */
            transition: all 2s ease 0s;
        }
        .box:hover {
            width: 1000px;
            height: 500px;
            background-color: turquoise;
            /* background-image: url(images/png/aichong05.png); */

        }
        .bar {
            width: 100px;
            height: 15px;
            border: 1px solid slategrey;
            border-radius: 3px;
        }
        .bar-in {
            width: 80px;
            height: 15px;
            background-color: lightpink;
            transition: width 2s;
        }
        .bar-in:hover {
            width: 100%;
        }
    </style>
</head>
<body>
    <div class="box"></div>
    <br><br><br>
    <div class="bar">
        <div class="bar-in"></div>
    </div>
</body>
</html>